Hi JH, and glad you finally found us!
Yes, to put it simply, the D models, or standalone Auber PID added to your current smoker, will eliminate those swings. Temps hold within a degree, so temp-sensitive smokes are never effected by the swings!
Even with the analog controller, if you are seeing +60° swings, it is probably due to combustion of your wood. Are you using chips or chunks, and what's the source of your wood? Not uncommon, with some of the big box store woods.